Grinding machine



R. N. HEALD 1,950,491

GRINDING MACHINE Filed May 5, 1928 2 Sheets-Sheet l gmc/wm GMI/M441March 13, 1934.

March 13, 1934. R N, HEALD 1,950,491

GRINDING MACHINE Filed May 5, 1928 2 Sheets-Sheet 2 Ro er N. HealdPatented Mar. 13, 1934 UNTE GRINDING MACHINE Application May 3, 1928,Serial No. 274,824

4 Claims.

The invention relates to internal grinding machines which are adapted togrind the internal peripheral surfaces of hollo-w cylinders, gears, ballraces, and other similar hollow or annular bodies. Such articlesfrequently have one or more shoulders breaking their internalcylindrical or conical surfaces, and much time is saved if suchshoulders, which generally constitute plane surfaces, can be ground atthe same time as the surfaces of revolution are ground; for one chuckingof the article then suffices for two or more operations.

The ordinary internal grinding machine is provided With a table orcarriage which, carrying either the grinding wheel or the work holder,serves to reciprocate one of these parts in relation to the other, sothat the grinding traverse of the wheel may be produced. In connectionwith such a table or carriage a reversing mechanism is provided whichmay take any one of several different forms, but which, Whatever form ittakes, depends for its operation on some reversing member actuated fromdogs or stops provided by the table or carriage, and which incorporatessome form of spring or fluid pressure snap over device to shift the mainreversing control means beyond the dead center, so that the table may bereversed and not come to a stop. Such snap over device whether it bespring actuated, fluid pressure actuated, or operated in some differentmode, is inherently uncertain in its action no matter how carefully itmay be made or adjusted. The usual grinding practice, when grindinginternal surfaces, is to cause the wheel to travel slightly beyond theopposite extreme limits of such surfaces, thus to insure grindingdespite slight variation in the range oi travel of the grinding carriagebut this, obviously, cannot be done in the case of a shoulderedworkpiece. One object of the invention therefore is to provide positivemeans for limiting the stroke of the table or carriage in one direction,so that internally shouldered objects may be ground right up to a sharpre-entrant corner, without danger of smashing the grinding wheel ordisrupting some other mechanism of the machine.

Another object of the invention is the grinding of these flat surfacesor shoulders themselves, and when it is required that this be done onthe same machine that grinds the surface of revolution, the front faceof the small internal grinding wheel must necessarily perform the task.To perform such an operation the wheel must Abe fed slowly intorthisfiat or shouldered surface at a rate commensurate with the ordinarycross o-r transverse feed provided by internal grinding machines, whichfeed is totally disproportionate to the relatively fast normallongitudinal movement of the table or carriage. At the same time, it ishighly desirable that the fluid pressure actuating and reversingmechanism, which has been found so useful in internal grinding machines,be retained. It is plain that the provision o-f any screw feed or thelike to move the table or carriage would complicate the machine andwould have to be connected and disconnected from the table to allow ofnormal iiuid pressure actuation thereof. The invention, therefore,provides a rigid stop for co-operation with the table or carriage inbringing the wheel to the shoulder, and incorporates means for varyingthe locus of the stop so as to provide for a very ne feed. The inventionfurther contemplates the combination of such variable stop with thefluid pressure actuating and controlling system, whereby the latterholds the table to the stop without possibility of lost motion. It willreadily be seen that results not obtainable with the use of a piniongear and rack, or a screw and nut means of reciprocating the table, areattained, the uid pressure system of actuation being resilient in itsnature while the others mentioned are positive and unyielding.

The above and other advantageous features of the invention willhereinafter more fully appear from the following detailed description,taken in connection with theaccompanying drawings, in which:-

Fig. 1 is a front elevation of a grinding machine embodying theinvention, showing certain parts of the fluid pressure actuatingmechanism in dotted lines. s

Fig. 2 is a fragmentary elevation of the adinstable positive stop whichis part of the invention, together with the table dog with which itoperates.

Fig. 3 is a plan view of the stop shown in Fig. 2.

Fig. 4 is a vertical sectional view taken on the line 4 4 of Fig. 3.

Fig. 5 is an end view of the table dog shown in Fig. 2.

Figs. 6 and '7 are diagrammatic views showing respectively how thegrinding wheel is adapted. to grind a shoulder at the far end of ahollow cylindrical body, and how the invention may be made use of togrind the front annular face of a work piece.

Like reference characters refer to like parts throughout the drawings.

Referring to Fig. 1, the machine provides the usual reciprocatory tableor carriage 1 which is toA present in most internal grinding machines,and by the reciprocation of which the grinding traverse between thewheel and the work is produced. Such table or carriage may carry eitherthe grinding wheel or the workpiece; as here shown said table supportsthe wheel head 2 While the work head 3 is supported by a bridge 4 whichspans the slide ways provided for the back and forth reciprocation ofthe table l. The grinding wheel 5 is mounted on the end of a spindle 6which is suitably journaled in the wheel head 2, and any suitable means,not shown, may be provided to rotate the grinding spindle, such meansforming no part of my present invention. By means of adjustable dogs orstops 7 and 8 carried by the table 1, a pivoted reversing member 9 isshifted, first in one direction and then in the opposite direction, thusproducing the normal working traverse of said table through the mediumof fluid pressure operating mechanism, which said member 9 controls.Such fluid pressure operating mechanism may and desirably does take theform shown in United States Letters Patent No. 1,582,468 granted toHeald and Guild on April 27, 1926 and comprises essentiallly a fluidpressure cylinder 10 which contains the usual double acting piston 1lsuitably connected, as by a rod 12 with the table 1. For the back andforth movement of said table 1, fluid under pressure is admitted to oneend or the other of the cylinder 10, the pressure fluid being forced bya pump 13 into a supply pipe 14, the latter leading to a reversing valvedesignated generally by the numeral 15; the position therein of amovable valve member, not shown, suitably connected to the reversingmember 9, determines the flow of the pressure medium to one end or theother of the cylinder 10 by way of a pipe 16 or a pipe 17 as the casemay be. The usual spring snapover device, not shown, is operative eitheron the member 9 or on the fluid-directing member in the valve 15, sothat the latter, when actuated by the reversing dogs 7 and 8, willalways pass through its neutral or center position. However a handle 18is provided on the front of the machine by means of which the reversingvalve may be manually placed in such neutral position. It is not deemednecessary to further describe the fluid pressure actuating and reversingmechanism, since any of the known forms thereof may be employed, andreference may be had to the aforesaid patent for any further details ofthe particular construction herein referred to.

Referring to Figs. 1 and 2, the table 1 carries a block 19 adjustablymounted thereon beyond the outer reversing dog 8. As is the case withthe blocks 26 and 21 that carry the reversing dogs '7 and 8, the block19 may be readily adjusted in its position longitudinally of said table1, as by means of the usual hand screw nuts 22, 22, 22, carried by allthree blocks and meshing with a screw rack 23 formed on the table. Asbest shown in Fig. 5, the block 19 is provided with a downwardly openingchannel 24, and received in this channel is a dog or stop 25, pivotallymounted on a pin 26 that extends across the channel. The lower orstriking end of the dog 25 normally extends below the bottom of theblock 19, and this striking end is rigid against movement to the rightin relation to the block, for the dog 25 cannot turn furthercounterclockwise than the position shown in Fig. 2 since an uppersurface 27 of said dog is in contact with the floor or inner surface ofthe channel. The dog 25, moreover, is resiliently prevented from turningin a clockwise direction by means of a ball and spring device 28 locatedin the block 19, the ball of which is adapted to seat in either of twodepressions 29 and 30 provided in the front fact of the dog, the lowerdepression 29 receiving said ball when the parts are in the positionshown, and the upper depression 30 receiving the ball when the strikingend of the dog is lifted, to render it inoperative for a purpose thatwill be pointed out hereinafter. By means of a suitable handle 31 thedog 25 can be easily and quickly placed in either of these positions bythe machine operator.

Suitably fastened to the front of the machine frame, as by means of thecap screws illustrated, is a bracket 32. Referring now toFig.4,thebracket 32 provides a vertical hole 33 extending therethrough whichconstitutes a bearing support for a shaft 34. Formed integrally with orfastened to the upper end of this shaft 34 is an eccentric of cam member35 which lies in the path of travel of the dog 25. The eccentric portion35 may be manually turned by means of a handle member 36 which providesa collar portion 37 that surrounds the shaft 34 and is fastened theretoas by a key and spline. Y

Referring to Figs. 2, 3 and 4, the above described parts are normallymaintained in the position shown in said figures by means of a coiledspring 38, one end of which exerts its torsion on the shaft 34 throughthe medium of a sleeve 39 having a projection lug 40, the other end ofsaid spring being anchored to the bracket 32 by means of a screw or bolt41. The action of the spring 38, as will be clearly apparent from thedrawings, tends to turn the shaft 34 and eccentric 35 in acounterclockwise direction as viewed in the plan view of Fig. 3. Theshaft and eccentric are prevented from turning beyond the position ofFig. 3 by means of a stop lug 42 projecting from the collar portion 37,which engages a lug 43 formed on the bracket 32.

When the machine is to be used for the internal grinding of unshouderedworkpieces, or workpieces having shoulders remote from their surfaces tobe ground, the dog 25 is rendered inoperative, by merely depressing thepin 31 and raising the striking end of the dog 25 above the top of theeccentric 35. When, however, it becomes desirable to grind a successionof workpieces a such as shown in Fig. 6 as closely as possible to aninternal flange b of each workpiece without any danger of the grindingwheel impacting said flange and being broken, the operator raises thepin 31 to place the striking end of the dog 25 on a level with theeccentric 35, and having first moved the table 1 to carry the grindingwheel 5 into the workpiece, he moves the lock 19 relative to the table 1until the dog 25 is actually touching the eccentric 35. The operatorthen shifts the control lever 18 so as to force the table 1 to the leftby fluid pressure, and turns the hand screw nut 22 provided by the block19 in the direction to allow the table to be slowly moved to the leftuntil the desired limit of required inward traverse of the grindingwheel is attained. The operator should then set the right-hand tablereversing dog 8 so that it has just shifted the reversing member 9beyond the dead center position in order that the travel of the tablewill be reversed at this point and, after establishing the right hand oroutward limit of the traverse in the well known manner, he causes thetable 1 to reciprocate slowly (which may be done by the use of thethrottle lever 43 on the front of the machine). If the table 1 in itsmovement to the left causes the dog 25 to strike the eccentric 35 thedog 8 should be shifted to reverse the member 9 slightly earlier, andthis may be done by means of vthehand screw nut 22 provided by the block21. In the grinding of the `workpiece a which can then be proceededwith, there will be no danger of the grinding wheel 5 striking theflange b and being fractured, as the dog 25 and the eccentric 35 willact as a positive fstop to limit the leftward motion of the table,

although the parts will have been set so that', barring some suddenchange in the pressure of the operating fluid or in the resistance ofthe ways on which-the table 1 travels. these members will not vquitecome into contact, or if they do so will barely touch gently.

The invention, however, has more extensive .use as a means whereby theplane surface of the flange b, Fig. 6, can itself be ground. In usingthe invention for this purpose, whether the internal cylindrical surfacec has been. ground or not, the operator moves the grinding wheel by themethod already described as near to the flange b without touching it ashe is able, by the use of good judgment, to do, it being understood thatthe hand lever 18 has been shifted to cause the pressure iiuid to enterthe right hand end of the cylinder 10 by way of the pipe 17 to force thetable 1 to the left, and that the striking end of the dog 25 is inactual engagement with the eccentric portion 35. The operator will thengrasp the handle 36 and turn it slowly clockwise against the tension ofthe springs 38. This causes the grinding wheel to be fed with a slowcutting feed to carry its front radial or annular surface d intoengagement with the flange b,

' since the eccentric member 35 is in its extreme right-hand positionwhen the parts are in the position shown in Figs. l and 3, and anymovement from that position will allow the dog 25 to move to the left.In case extreme motion of the eccentric does not result in any Contactbetween the grinding wheel and the flange b, the operator can return theeccentric to its initial position and feed the table inwardly by use ofthe screw 22 on the block 19 and repeat the operation.

-' When, ultimately, the flange b has been ground to the required depth,as determined in any manner such as by the use of a gage, the operatormay preserve the trial result thus brought to a conclusion by means of ascrew or pin 44, which can be located in any one of a plurality of holesprovided in a web 46 extending horizontally from the member 32, andwhich, together with a set screw 47 provided by the handle 36,constitute locating stops to enable the parts to again be moved to theexact position found. To do this it is only necessary to locate the stopscrew 44 close to the screw 47 and then turn the latter until it engagesthe stop screw 44; the screw 47 can then be locked in position as bymeans of a screw binding device 48 actuated from a bolt 49. The operatorcan then grind a whole series of flanges b on workpieces a to the samedepth as the first one of the series was ground, and when the screw 47contacts with the stop screw 44, the

operator will know that the operation is finished.

The invention further provides a ready means for causing the table 1 toundergo its normal reciprocatory traverse under the control of thereversing dogs 7 and 8, and to be then quickly moved to the left tocarry the stop 25 into engagement with the eccentric or cam portion 35.This means has particular utility in case it is desired, first, to grindthe internal cylindrical surface c of the workpiece a, and subsequentlyto grind the side of the ange b, without in any.,

the location of engagement of manner'changing the setting of themachine. To this end, the right-hand table dog 8, which normally limitsthe left-hand motion of the table l that carries the. grinding wheel 5into the workpiece, is a pivotally mounted dog. As best shown in Fig. 2,the dog 8 nts in a chanel 50 provided on the under portion of itscarrying block 21, in much the same fashion that the dog 25 fits in thechannel 24; the dog 8 is pivotally mounted in said channel on a pivotpin 51 extending thereacross, and is normally maintained in the positionshown in Fig. 2 by a spring 52. Assuming the carrying blocks 20 and 21of the table dogs 7 and 8 to have been so adjusted relative to saidtable that the grinding wheel 5 undergoes a traverse to properly grindthe internal cylindrical surface c of the workpiece a, the operator whensaid grinding .operation is finished has only to press downwardly a pin52 on the right-hand end of the dog 8, and this raises the striking. endof said dog above the reversing member 9 and allows the table l to moveto the left until the striking end of the dog 25 comes in contact withthe member 35, which will have been previously adjusted to properposition to stop the table just before the front of the grinding wheelstrikes the flange b in the workpiece, as hereinbefore described. Theoperator may now swing the lever 37 in a clockwise direction, or to theleft, until the already adjusted set screw 47 strikes the pin 44, andnow the grinding of the workpiece aL to both the cylindrical surface cand the flange b is completed in practically one operation. It will bereadily seen that this operation can be performed very rapidly.

The workpiece being now completed, the operator need only run thegrinding wheel 5 to its inoperative position relative to the work head3, this being done by causing movement of the table 1 to the rightbeyond its normal working traverse in a manner which forms no part ofthe present invention, but which for illustrative purposes is shown asembodied in the pivotal mounting of the table dog 7, and the provisionof a hand lever 53, which has an inclined surface 54 adapted to beraised into the path of said table dog 7 to cause it to be lifted overthe reversing member 9, thus allowing the table to continue itsright-hand movement to separate the grinding wheel and the workpiece,the table being brought to a stop in its retracted position by anysuitable means, such as that disclosed in the aforesaid patent to Healdand Guild. The operator may now place a new workpiece a in the chuck andrepeat the grinding operation, the setting of the adjustable stops ofthe invention and also the table reversing dogs 7 and 8 beingundisturbed.

The apparatus of the invention can also be made use of to grind thefront annular surfaces e of a workpiece a, as shown in Fig. 7, but theprocedure for performing this operation, being in all respectssubstantially similar to that already described in connection with thegrinding of the face of the flange b, it need not be herein further setforth.

I claim,

1. In a grinding machine, a positive stop comprising an eccentric or cammember suitably journaled in the frame of the machine, a cooperatingstop carried by a table or carriage, means to swing said rst named stopto change the second stop therewith, and adjustable means to limit theswing of the first named stop to bring it to a `desired position.

2. In a grinding machine, a positive stop comprising an eccentric or cammember suitably journaled in the frame of the machine, a cooperatingstop carried by a table or carriage, means to swing said rst named stopto change the location of engagement of the second stop therewith, andspring means to swing said stop in a retrograde direction and furthermeans to x the initial position of said first stop to locate the surfacethereof in reference to the other stop so as to x the initial positionof engagement therebetween.

3. In a grinding machine, a reciprocatory table for producing a relativeaxial traverse between a grinding wheel and a workpiece, uid pressuremechanism for reciprocating said table, including a reversing member andstops on said table to engage and shift said member in oppositedirections, thereby to effect successive reversals of the table travel,in combination with means operating independently of said reversingmember and stops for positively limiting the extent of table travel inone direction, said means comprising a projection on said table and anabutment in the path of said projection, and means for operating saidlast-mentioned parts to procure an axial feed of the grinding Wheel,

4. In a grinding machine, a base member, a table member movable on saidbase member, a positive stop comprising an eccentric or cam suitablyiournaled in one of said members, a cooperating stop carried by theother of said members, means to swing said first named stop to changethe location of engagement of the second stop therewith, and adjustablemeans to limit the swing of the first named stop to bring it to thedesired position.

ROGER N. HEALD.

